1. Field of the Invention
The present invention relates to a method for controlling a memory address of an external memory and/or an internal memory of a digital signal processor.
2. Description of the Prior Art
A digital signal processor (hereinafter referred to as a DSP) has an ability to perform a higher accurate processing compared to an analog signal processor. The DSP has features in that it is capable of evenly obtaining arbitrary characteristics by setting parameters such as coefficients and achieving non-adjustment. Moreover, the DSP is capable of processing an analog signal by means of a digitizing method. For this reason, this DSP has been used in a wide field such as a voice signal processing, a communication signal processing, a measurement signal processing, an image signal processing, an earthquake wave signal processing and a underwater acoustic signal processing.
An ordinary DSP is not designed assuming that it processes a plurality of independent programs in a time-shared fashion within a period of time of one sampling time. For this reason, in a case where the plurality of independent programs are processed within one sampling time, used areas of an internal data memory (D-RAM) and an external memory (X-RAM) has been used after dividing them with each program and coefficient. However, when a plurality of jobs are executed in parallel, a disadvantage has been occurred that a memory address is not managed independently for each job, but an access may be done for a memory area of other jobs while one job is being executed.
Moreover, although the jobs executed in parallel are the same, a program must be stored independently in the memory for each job, the program having the same content as those of others so that the quantity of job programs of a host CPU becomes disadvantageously large. For this reason, the types of the jobs which can be stored in the memory are limited.